JP3287168B2 - Full-color development toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a full-color developing toner used in a full-color image forming apparatus such as a full-color copying machine and a full-color printer, and relates to a color toner comprising a cyan toner, a magenta toner and a yellow toner. The present invention relates to a full-color developing toner used in a full-color image forming apparatus for forming a full-color image using a black toner.

[0002]

2. Description of the Related Art In recent years, full-color image forming apparatuses such as full-color copying machines and full-color printers which form full-color images using toners of a plurality of colors have been used. In the forming apparatus, to develop a full-color image,
A full-color developing toner using a black toner in addition to a color toner including a cyan toner, a magenta toner, and a yellow toner has been used.

Here, there are various types of such full-color image forming apparatuses, and generally, a magenta, a magenta, or the like is formed by a writing means for irradiating a charged photoreceptor with a light beam such as a laser. An electrostatic latent image corresponding to a predetermined color selected from cyan, yellow, and black is formed, and a magenta toner, a cyan toner, a yellow toner, and if necessary, a black toner are formed on the electrostatic latent image. A predetermined selected toner is supplied to perform development, the latent image forming step and the developing step are performed for each color, and these toner images are superimposed to obtain a full-color image.

On the other hand, in such a full-color image forming apparatus, in addition to forming a full-color image as described above, a normal monochrome image is formed using only black toner.

Here, in producing a cyan toner, a magenta toner, a yellow toner, and a black toner used in the above-described full-color image forming apparatus, conventionally, the same resin is generally used as a binder resin in each of the above toners. Was like that.

However, when the black toner is formed of the same binder resin as other color toners such as the cyan toner, if only the black toner is frequently used to form a monochrome image as described above, There is a problem that this black toner deteriorates faster than other color toners such as cyan toner, and when a full-color image is formed, the gloss of the black image portion formed by this black toner is too emphasized and conspicuous. There is also a problem that a sense of incongruity occurs with a portion of a color image formed by the color toner.

On the other hand, a black toner conventionally used for forming a monochrome image has a lower gloss than a color toner used in a full-color image forming apparatus. When an image is formed, there is a problem that a difference in gloss between a black image portion and a color image portion is increased to cause a sense of incongruity, and a satisfactory full-color image cannot be obtained.

[0008]

SUMMARY OF THE INVENTION The present invention is used in a full-color image forming apparatus for developing a full-color image by developing each predetermined color using cyan toner, magenta toner, yellow toner and black toner. It is an object of the present invention to solve the above-mentioned problems in a full-color developing toner.

That is, according to the present invention, in the above-described full-color image forming apparatus, even when a normal monochrome image is frequently formed using only a black toner in addition to a full-color image, only the black toner is used as a cyan toner. It does not deteriorate faster than other color toners, and when a full-color image is formed, the gap between the black image portion formed by the black toner and the color image portion formed by the color toner It is therefore an object of the present invention to provide a good full-color image and a stable formation of a monochrome image, with little occurrence of discomfort.

[0010]

According to the present invention, in order to solve the above-mentioned problems, a full-color image is developed by performing development for each predetermined color using cyan toner, magenta toner, yellow toner and black toner. in full color developing toner for use in full-color image forming apparatus for forming a said cyan toner, a flow starting temperature Ti ₁ is 80 to 100 ° C. of the binder resin in the color toner of magenta toner and yellow toner, a softening point T
m ₁ is 90 to 120 ° C., and the difference ΔT ₁ (= Tm ₁ −Ti ₁ ) between the softening point Tm ₁ and the outflow starting temperature Ti ₁ is 10 to 2
0 ° C., the outflow starting temperature Ti ₂ of the binder resin of the black toner is 90 to 110 ° C., and the softening point Tm ₂ is 1
10 to 130 ° C., the above softening point Tm ₂ and outflow starting temperature Ti
₂ , the difference ΔT ₂ (= Tm ₂ −Ti ₂ ) is 15 to 30 ° C., and the difference (ΔT ₂ −ΔT) between ΔT ₂ in this black toner and ΔT ₁ in each of the above color toners.
₁ ) was set to 3 to 13 ° C.

Here, the outflow starting temperature Ti _{1 of} the binder resin used for the above color toner and the black toner,
Ti ₂ and softening points Tm ₁ and Tm ₂ were measured using a flow tester (CFT-500, manufactured by Shimadzu Corporation), and 1.0 g of a sample was weighed.
mm × 1.0mm die, temperature rise rate 3.0 ° C./m
in, a preheating time of 180 seconds, a load of 30 kg, and a measurement temperature range of 60 to 140 ° C., and a temperature at which the sample began to flow was defined as a temperature at which the sample began to flow. The softening point was Tm.

[0012] Then, in the toner for full color development in the present invention, the above cyan toner, the binder resin in the color toner comprising a magenta toner and yellow toner, its flow starting temperature Ti ₁ is 80 to 10
The use of a material having 0 ° C. and a softening point Tm ₁ of 90 to 120 ° C. is a reason why an outflow starting temperature Ti ₁ is lower than 80 ° C. or a material having a softening point Tm ₁ lower than 90 ° C. While the offset is likely to occur, the outflow start temperature Ti ₁
Is higher than 100 ° C., the fixing strength of these toners decreases, and the softening point Tm ₁ is 120 ° C.
When a higher one is used, the thermal fusibility at the time of fixing decreases, thereby lowering the fixing strength, and the glossiness and light transmittance of a full-color image, and further, the color mixing property of each toner is reduced, which is favorable. a full-color image is because the can not be obtained, preferably, a flow starting temperature Ti ₁ described above 80 to 95 ° C., a softening point Tm ₁ is to use one of 95 to 115 ° C..

The difference ΔT ₁ (= Tm ₁₎ between the softening point Tm ₁ and the outflow start temperature Ti ₁ in the above binder resin.
−Ti ₁ ) at 10 to 20 ° C.
When T ₁ is less than 10 ° C., while the high-temperature offset tends to occur, when the [Delta] T ₁ is higher than 20 ° C., is because the translucency and color mixing of the toner is lowered, preferably, the [Delta] T ₁ is 10 １５15 ° C.

On the other hand, the reason why the outflow starting temperature Ti ₂ is 90 to 110 ° C. and the softening point Tm ₂ is 110 to 130 ° C. for the binder resin in the black toner is that the outflow starting temperature Ti ₂ is 90 low and than ° C., if the softening point Tm ₂ was used as less than 110 ° C., the strength of the binder resin is lowered, while the durability of the resulting toner becomes poor, the flow starting temperature Ti ₂ If a material having a softening point higher than 110 ° C. or a material having a softening point higher than 130 ° C. is used, the thermal fusibility at the time of fixing is reduced, thereby lowering the fixing strength and the gloss. Preferably, the above-mentioned outflow starting temperature T
i ₂ is 95 to 105 ° C., and softening point Tm ₂ is 115 to 130
° C.

The difference Δ between the softening point Tm ₂ of the binder resin of the black toner and the outflow start temperature Ti ₂ is shown.
The reason for using T ₂ (= Tm ₂ −Ti ₂ ) of 15 to 30 ° C. is that if ΔT ₂ is lower than 15 ° C., the durability of the toner is deteriorated, while ΔT ₂ is higher than 30 ° C. This is because the gloss of the black toner is reduced and a sense of incompatibility is generated between the gloss of the other color toners. Preferably, ΔT ₂ of 20 to 30 ° C. is used.

Further, the difference (ΔT ₂ −ΔT ₁ ) between ΔT ₂ in the binder resin of the black toner and ΔT ₁ in the binder resin of the color toner is 3 to _1.
The reason why the temperature is set to 3 ° C. is that when the difference is larger than 13 ° C., the black toner is less likely to melt at the time of fixing than the color toner, and the gloss of the black image by the black toner and the gloss of the color image by the color toner are fixed. When the difference is smaller than 3 ° C., if the difference is smaller than 3 ° C., the gloss of the black image portion in the full-color image is excessively emphasized, or the durability of the black toner is reduced. Is about the same as the durability of the color toner, and when a large number of monochrome images such as character images are formed, the life of the black toner is shortened. For example, the amount of toner conveyed by the toner carrier is regulated by a toner regulating member. This black toner aggregates when used in a one-component developing system in which the toner is charged and the toner is charged. When used in a two-component developing type developing device that adheres to a toner regulating member or a toner carrier to form a formed image, or is mixed with a carrier, the toner component adheres to the carrier and causes spent. This is because the carrier deteriorates, the toner is not properly charged, and a problem such as fogging of a formed image occurs.

Here, as the binder resin in each of the above toners, for example, a styrene-acrylic resin,
A polyester-based resin, an epoxy-based resin, or the like can be used, but it is preferable to use a polyester-based resin in terms of the durability and the light-transmitting properties of the resin.

In order to obtain sufficient strength, heat resistance and the like while having sufficient sharp melt characteristics, translucency and color mixing properties, such a polyester resin is etherified with an alcohol component. Diphenols,
It is preferable to use an acid component using an aromatic dicarboxylic acid.

The etherified diphenols used for the alcohol component include, for example, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxypropylene (3.3) −
2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, polyoxypropylene (2.0) -polyoxyethylene (2. 0) -2,2-
Bis (4-hydroxyphenyl) propane, polyoxypropylene (6) -2,2-bis (4-hydroxyphenyl) propane and the like can be used.

In order to adjust the glass transition point and softening point of the polyester resin, alcohol components other than the above-mentioned etherified diphenols, for example, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene Glycol, 1,3
Diols such as propylene glycol, 1,4-butanediol, neopentyl glycol; sorbitol;
1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, -Methylpropanetriol, 2-methyl-
A small amount of a polyhydric alcohol such as 1,2,4-butanetriol, trimethylolethane, trimethylolpropane, and 1,3,5-trihydroxymethylbenzene may be added.

On the other hand, as the aromatic dicarboxylic acids, for example, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, acid anhydrides thereof and lower alkyl esters thereof can be used.

In order to adjust the glass transition point and softening point of the polyester resin, in addition to the above-mentioned aromatic dicarboxylic acids, for example, fumaric acid, maleic acid, succinic acid, alkyl or alkenyl having 4 to 18 carbon atoms. A small amount of an aliphatic dicarboxylic acid such as succinic acid or an aliphatic anhydride thereof such as an acid anhydride or lower alkyl ester thereof may be added.

Further, in order to adjust the acid value of the polyester resin and to improve the resin strength, other than the above, for example, 1,2,4-benzenetricarboxylic acid (trimellitic acid), 1,2 , 5-benzenetricarboxylic acid, 2,5,7-naphthalenetricarboxylic acid,
1,2,4-naphthalenetricarboxylic acid, 1,2,4-
Butanetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, 1,2,4-cyclohexanetricarboxylic acid, tetra (methylenecarboxyl) methane, Polycarboxylic acids such as 2,7,8-octanetetracarboxylic acid, pyromellitic acid, anhydrides thereof and lower alkyl esters thereof may be added in a small amount as long as the light transmittance of the toner is not impaired. . However, regarding the black toner, it is not particularly necessary to consider the translucency and the like.

It is also possible to use a urethane-modified polyester resin obtained by reacting an isocyanate with a polyester resin, and particularly, it can be suitably used as a binder resin for a black toner. This is because the black toner has a higher softening point and the like than the color toner so that the black toner has a sufficient strength.

In the full-color developing toner of the present invention, an appropriate colorant is added to the binder resin so that the cyan toner, the magenta toner, the yellow toner and the black toner show respective colors. Magenta, cyan, yellow, and black colorants as shown in Table 1 can be used, but are not particularly limited to these colorants.

Here, as the magenta colorant, for example, C.I. I. Pigment Red 1, 2, 3, 4, 5,
6, 7, 8, 9, 10, 11, 12, 13, 14, 1
5, 16, 17, 18, 19, 21, 22, 23, 3
0, 31, 32, 37, 38, 39, 40, 41, 4
8, 49, 50, 51, 52, 53, 54, 55, 5
7, 58, 60, 63, 64, 68, 81, 83, 8
7, 88, 89, 90, 112, 114, 122, 12
3, 163, 184, 202, 206, 207, 209
Magenta pigments such as C.I. I. Solvent Red 1,
3, 8, 23, 24, 25, 27, 30, 49, 81,
82, 83, 84, 100, 109, 121, C.I. I.
Disperse Red 9, C.I. I. Basic Red 1,
2, 9, 12, 13, 14, 15, 17, 18, 22,
23, 24, 27, 29, 32, 34, 35, 36, 3
Magenta dyes such as 7, 38, 39, and 40 can be used.

Further, as the cyan colorant, for example,
C. I. For example, cyan pigments such as CI Pigment Blue 2, 3, 15, 16, 17 and the like can be used.

As the yellow colorant, for example,
C. I. Pigment Yellow 1, 2, 3, 4, 5, 6,
7, 10, 11, 12, 13, 14, 15, 16, 1
7, 23, 65, 73, 83, C.I. I. Yellow pigments such as Vat Yellow 1, 3, and 20; I. Yellow dyes such as Solvent Yellow 79 and 162 can be used.

As the black colorant, carbon black or the like can be used.

Here, in each of the above-described full-color developing toners, in particular, in each of the cyan, magenta and yellow toners, a flushing treatment is performed so that the colorant is uniformly dispersed in the binder resin. By using a colorant with improved dispersibility by using, or a master batch in which the colorant is previously dispersed in a binder resin is manufactured, and the master batch is kneaded with the binder resin, and the colorant is added to the binder resin. It is preferable to perform a masterbatch process of dispersing the mixture in a batch.

Regarding the amount of the coloring agent to be contained,
It is preferable to add 2 to 15 parts by weight based on 100 parts by weight of the binder resin. That is, when the amount of the colorant is in this range, the above-mentioned color toner particularly has a sufficient light transmittance and is suitable for developing on an OHP film or the like.

In the full-color developing toner according to the present invention, in addition to the binder resin and the colorant described above, a charge control agent is used to adjust the chargeability of the toner and to improve the fluidity of the toner. And various additives such as a post-treatment agent.

Here, as the charge control agent, it is preferable to use a colorless, white or light-colored charge control agent so as not to adversely affect the color tone and light transmittance of toners of various colors. And a charge control agent such as a salicylic acid metal complex of a salicylic acid derivative and a metal such as zinc, a calixarene-based compound, a boron compound, and a fluorinated quaternary ammonium salt-based compound.

Examples of the salicylic acid metal complex include those described in JP-A-53-127726 and JP-A-62-145255, and examples of the calixarene-based compound include, for example, those described in 2-2
For example, compounds described in JP-A No. 01378 and the like and boron compounds are described in, for example, JP-A-2-221967 and fluorine-containing quaternary ammonium salt-based compounds are described in Those described in, for example, JP-A-1162 can be used. Further, in order to adjust the charge amount of the toner and to improve the rising property of charging, a fluorine-containing quaternary ammonium salt-based compound is used in combination with a charge control agent such as a salicylic acid metal complex or a calixarene-based compound. It is also possible.

Here, when the above-mentioned charge control agent is added, a binder is usually used so that the toner has appropriate chargeability and the charge control agent is well bound to the binder resin. 0.1 to 10 parts by weight, preferably 0.5 to 5.0 parts by weight per 100 parts by weight of the resin.
Add parts by weight.

As the post-treating agent, for example, silica, alumina, titania, tin oxide, zirconium oxide, etc. can be used alone or in combination of two or more. It is preferable to use those subjected to a hydrophobizing treatment in order to enhance the stability. Examples of the hydrophobizing agent include various coupling agents such as silane, titanate, aluminum, and zircoaluminate, and silicone oil. Can be used.
In particular, as the above-mentioned post-treatment agent, it is preferable to use a combination of hydrophobic silica and hydrophobic titania, or a combination of hydrophobic silica and hydrophobic alumina, from the viewpoint of fluidity of the toner and environmental stability against charging. The amount of the post-treatment agent added is 0.2 to 3.0% by weight based on the toner in order to increase the fluidity of the toner and prevent the post-treatment agent from releasing and adversely affecting the toner. It is preferable to make it.

In producing the full-color developing toner according to the present invention, it is preferable to produce the toner by a kneading and pulverizing method from the viewpoint of reducing the production cost and improving the production stability.

Here, in producing a toner by a kneading and pulverizing method, the above-mentioned polyester resin, a colorant and, if necessary, the above-mentioned various additives are added, and these are mixed by a mixer such as a Henschel mixer. After the mixture is melted and kneaded, the kneaded material is cooled, then coarsely pulverized, the coarsely pulverized particles are further finely pulverized, and the obtained finely pulverized particles are classified to obtain a toner. I do. When the toner is manufactured in this manner, the volume average particle diameter of the toner is 5 to 10 from the viewpoint of improving the reproducibility of a highly delicate image.
It is preferable to adjust so as to be in the range of μm.

The full-color developing toner of the present invention can be used as a two-component developing toner used with a carrier or as a one-component developing toner without using a carrier. In the two-component developing method in which stirring is performed, the volume in the developing device is increased, and there is a restriction in reducing the size of the image forming apparatus. In addition, an edge effect is easily generated in a formed image, and a solid image is formed. Since it is disadvantageous for a frequent full-color image, it is more advantageous to use it in a one-component developing system in which the influence of an edge effect is small and a flat solid image can be formed.

When the toner is used as a magnetic toner also in the one-component developing method, black magnetic powder is usually added, so that the color of each of the cyan, magenta and yellow color toners is reduced and the toner is obtained. In addition, since the sharpness and color tone of a full-color image deteriorate, it is preferable to use the toner as a non-magnetic one-component toner. However, black toner has little effect on color, and can be used in either a non-magnetic toner or a magnetic toner state.

The full-color developing toner of the present invention is selected from magenta, cyan, yellow, and black on a uniformly charged photoreceptor by, for example, writing means such as irradiating a light beam. An electrostatic latent image corresponding to a predetermined color is formed, and the latent image is developed with a predetermined toner selected from magenta toner, cyan toner, yellow toner, and black toner, and the toner image is transferred onto an intermediate transfer member. After performing each process for each color sequentially, the toner image superimposed on the intermediate transfer body is transferred onto a recording member and fixed, or formed on the photosensitive member in the same manner as the above-described apparatus. The electrostatic latent image corresponding to the predetermined color is developed with a predetermined toner selected from magenta toner, cyan toner, yellow toner, and black toner. After the step of transferring the toner image to the recording member held on the intermediate transfer member is sequentially performed for each color, the image forming apparatus is configured to fix the toner image superimposed on the recording member, or the same as the above-described apparatus. Developing an electrostatic latent image corresponding to a predetermined color formed on the photoreceptor with a predetermined toner selected from magenta toner, cyan toner, yellow toner, and black toner; Is performed for each color to form a superimposed toner image on the photoreceptor, and the toner image can be transferred to a recording member and used for an image forming apparatus or the like.
It should be noted that among these image forming apparatuses, the above-described apparatus for transferring each toner image onto an intermediate transfer member and superimposing the toner images, and transferring the photosensitive member to the intermediate transfer member and the transfer from the intermediate transfer member to the recording member. Is preferable from the viewpoint of miniaturization.

[0042]

In the toner for full-color development in the present invention, the binder resin in each color toner of cyan toner, magenta toner and yellow toner and the binder resin in black toner satisfying the above-mentioned conditions are used. In addition, in a full-color image forming apparatus, in addition to forming a full-color image, even when a normal monochrome image is frequently formed using only a black toner, only the black toner is higher than a color toner such as a cyan toner. Does not deteriorate quickly, and when a full-color image is formed, there is a difference in gloss, etc., between the black image portion formed by the black toner and the color image portion formed by the color toner. Is also reduced.

[0043]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to embodiments, but the present invention is not limited to these embodiments.

As the binder resin in each of the toners of Examples and Comparative Examples, polyester resins A to E produced as described below were used.

(Polyester Resins A and B) In producing these polyester resins A and B, polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as PO) is used. ), Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (hereinafter abbreviated as EO), and terephthalic acid (hereinafter abbreviated as TPA) in a molar ratio. 3:
These were placed in a 2-liter four-necked flask in a ratio of 7: 9, and a reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were added to the four-necked flask. Attach and heat and stir these while introducing nitrogen into the flask from the nitrogen gas introduction tube, and monitor the reaction state while measuring the acid value during this reaction, to achieve a predetermined acid value. The reaction was terminated when the temperature reached, and the softening point Tm and the outflow starting temperature Ti were adjusted as shown in Table 1 below.
The polyester resin A and the polyester resin B having the values shown in the following were obtained.

(Polyester Resin C) In producing the polyester resin C, the molar ratio of PO, EO, fumaric acid, and TPA is set to be 5: 5: 5: 4, and otherwise, , The polyester resin A,
The reaction was carried out in the same manner as in the case of B to obtain a polyester resin C having a softening point Tm and an outflow starting temperature Ti having the values shown in Table 1 below.

(Polyester Resin D) In producing this polyester resin D, the above PO was
g, 659 g of isophthalic acid, and 90 g of diethylene glycol in a 5-liter four-necked flask at a ratio of 90 g.
A reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were attached to the four-necked flask, and placed in a mantle heater. Nitrogen gas was introduced into the flask from the nitrogen gas inlet tube. While at 220 to 270 ° C, dehydration polycondensation was performed to obtain a low molecular weight polyester resin.

On the other hand, 1720 g of the above PO, 1028 g of isophthalic acid, 328 g of 1,6-dipropyl-1,6-hexanediol, and 74.6 g of glycerin were put into a 5-liter four-necked flask at a ratio of: A reflux condenser, a water separator, a nitrogen gas inlet tube, a thermometer, and a stirrer were attached to the four-necked flask as described above, and the flask was placed in a mantle heater, and nitrogen was introduced into the flask from the nitrogen gas inlet tube. Dehydration polycondensation was performed at 240 ° C. while introducing gas to obtain a polyester resin for polymerization.

Then, 75 parts by weight of the above-mentioned low molecular weight polyester resin and 25 parts by weight of the polyester resin for polymerization were put into a Henschel mixer, and mixed and stirred sufficiently uniformly. ,
After adding 40 parts by weight of 4-diisocyanate and reacting at 120 ° C. for 1 hour in a pressure kneader, the percentage of NCO was measured and it was confirmed that the remaining free isocyanate groups had almost disappeared. A polyester resin D composed of a urethane-modified polyester resin having a starting temperature Ti having a value shown in Table 1 below was obtained.

(Polyester Resin E) In the production of the polyester resin E, in the production of the polyester resin D, the ratio of the low-molecular-weight polyester resin to the high-molecular-weight polyester resin was changed. The resin is used in an amount of 60 parts by weight, and the polyester resin for polymerization is used in an amount of 40 parts by weight. Otherwise, in the same manner as in the case of the polyester resin D, the softening point Tm and the outflow start temperature Ti are set as follows. This polyester resin E having the values shown in Table 1 was obtained.

The softening point Tm and outflow starting temperature Ti of each of the polyester resins A to E are values measured as described above using a flow tester.

[0052]

[Table 1]

Next, each of the above polyester resins A to E was used as a binder resin, and the cyan toners C1 to C4, the magenta toners M1 to M4, the yellow toners Y1 to Y4, and the black toners B1 to B5 were used as follows. Was obtained.

(Cyan Toner C1)
In producing the polyester resin 1, the polyester resin A
And a cyan coloring agent (CI Pigment Blue 15-3, manufactured by Toyo Ink Mfg. Co., Ltd.) at a ratio of 7: 3 in a pressure kneader, kneading them, and pulverizing the kneaded material with a feather mill. A pigment master batch was obtained.

Then, 10 parts by weight of the pigment masterbatch, 93 parts by weight of the polyester resin A, and 2 parts by weight of a charge control agent comprising a zinc salicylate complex (E-84, manufactured by Orient Chemical Co.) were used. Are mixed with a Henschel mixer, and the mixture is kneaded with a twin-screw extruder. After the kneaded product is cooled, the mixture is coarsely pulverized with a feather mill, further finely pulverized with a jet mill, and classified to obtain a volume average. Toner particles having a particle size of 8.0 μm were obtained.

Then, hydrophobic silica (H1303, manufactured by HDK) as an external additive was added to the toner particles.
8% by weight and 1.0% by weight of hydrophobic titania A having a hydrophobicity of 60% manufactured as described below were added, and these were mixed by a Henschel mixer and subjected to an addition treatment to obtain the cyan toner C1. Obtained.

Here, as for the above-mentioned hydrophobic titania A, titania having an average primary particle diameter of 50 nm (manufactured by Teica Corporation:
MT600B) was mixed and stirred in an aqueous system, and n-hexyltrimethoxysilane was converted to 20 parts of titania in terms of solid content.
% By weight, and dried and crushed to obtain hydrophobic titania A having a hydrophobicity of 60%. For the degree of hydrophobicity, 50 ml of pure water was placed in a 200 ml beaker, 0.2 g of a sample to be measured was added thereto, and methanol dehydrated with anhydrous sodium sulfate was added thereto with stirring from a burette. The point at which the sample was hardly seen on the liquid surface was defined as the end point, and the degree of hydrophobicity was calculated from the required amount of methanol by the following equation. Hydrophobicity = [Methanol usage / (50 + Methanol usage)] × 100

(Cyan Toner C2)
In producing the toner No. 2, a polyester resin B was used instead of the polyester resin A in the cyan toner C1.
Was used, and otherwise, a cyan toner C2 was obtained in the same manner as the cyan toner C1.

(Cyan toner C3) This cyan toner C
In producing the toner No. 3, the polyester resin C was used instead of the polyester resin A in the cyan toner C1.
Was used, and otherwise, a cyan toner C3 was obtained in the same manner as the cyan toner C1.

(Cyan Toner C4) This cyan toner C
In producing the toner No. 4, toner particles using the polyester resin A were obtained in the same manner as in the case of the cyan toner C1, and then hydrophobic silica (manufactured by HDK: H1303) was added in an amount of 0.4% by weight, and 0.6 parts by weight of hydrophobic titania B having a hydrophobicity of 60% manufactured as described below was added, and these were mixed with a Henschel mixer to perform an addition treatment. This cyan toner C4 was obtained.

Here, as for the above-mentioned hydrophobic titania B, titania having an average primary particle size of 15 nm (manufactured by Teica:
MT150A) A solution obtained by diluting 5 parts by weight of dimethylpolysiloxane having a viscosity of 500 centistokes at 25 ° C. with 50 parts by weight of xylene with respect to 100 parts by weight at 25 ° C. was spray-dried, and then dried. Was heated and crushed to obtain hydrophobic titania B having a hydrophobicity of 60%. The degree of hydrophobicity of the hydrophobic titania B was also calculated in the same manner as in the case of the hydrophobic titania A.

(Magenta Toner M1) In producing the magenta toner M1, a magenta pigment (CI Pigment Red 184, manufactured by Dainippon Ink and Chemicals, Inc.) was used as a colorant. A magenta toner M1 using the polyester resin A was obtained in the same manner as in the case of the cyan toner C1.

(Magenta Toner M2) In manufacturing the magenta toner M2, a polyester resin B is used in place of the polyester resin A in the above-described magenta toner M1, and otherwise the same as in the case of the magenta toner M1 Thus, magenta toner M2 was obtained.

(Magenta Toner M3) In producing the magenta toner M3, a polyester resin C is used in place of the polyester resin A in the above-described magenta toner M1, and otherwise the same as in the case of the magenta toner M1 Thus, a magenta toner M3 was obtained.

(Magenta Toner M4) In producing the magenta toner M4, a magenta pigment (CI Pigment Red 184, manufactured by Dainippon Ink and Chemicals, Inc.) was used as a colorant. A magenta toner M4 using the polyester resin A was obtained in the same manner as in the case of the cyan toner C4.

(Yellow Toner Y1) In producing the yellow toner Y1, a yellow pigment (CI Pigment Yellow 17 manufactured by Toyo Ink Mfg. Co., Ltd.) is used as a coloring agent. Yellow toner Y1 using polyester resin A was obtained in the same manner as in the case of cyan toner C1.

(Yellow Toner Y2) In producing the yellow toner Y2, a polyester resin B is used in place of the polyester resin A in the above yellow toner Y1, and otherwise the same as in the case of the yellow toner Y1 Thus, a yellow toner Y2 was obtained.

(Yellow Toner Y3) In producing the yellow toner Y3, a polyester resin C is used in place of the polyester resin A in the yellow toner Y1, and otherwise the same as in the case of the yellow toner Y1 Thus, a yellow toner Y3 was obtained.

(Yellow Toner Y4) In producing this yellow toner Y4, a yellow pigment (CI Pigment Yellow 17 manufactured by Toyo Ink Mfg. Co., Ltd.) is used as a colorant. In the same manner as in the case of the cyan toner C4, a yellow toner Y4 using the polyester resin A was obtained.

(Black Toner B1) In producing this black toner B1, 100 parts by weight of polyester resin D, 5 parts by weight of carbon black (Cabot Corp .: Mogal L), and a charge control agent (Orient Chemical Corp .: Bontron S-34), 2 parts by weight, low molecular weight polypropylene (manufactured by Sanyo Chemical Industries, Ltd .: Viscol TS-20)
0) in a ratio of 2.5 parts by weight, these were mixed with a Henschel mixer, and the mixture was kneaded with a twin-screw extruder and kneaded. After cooling the kneaded material, the mixture was coarsely pulverized with a feather mill. The powder was further pulverized with a jet mill and classified to obtain toner particles having a volume average particle size of 8.0 μm.

As an external additive to the toner particles, hydrophobic silica (Taranox T50, manufactured by Talco) is used.
0) was added in an amount of 0.5% by weight, and these were mixed by a Henschel mixer and subjected to an addition treatment to obtain a black toner B1.

(Black Toner B2) In producing the black toner B2, a polyester resin E is used in place of the polyester resin D in the above black toner B1, and otherwise the same as in the case of the black toner B1 Thus, a black toner B2 was obtained.

(Black Toner B3) In producing the black toner B3, a polyester resin A is used in place of the polyester resin D in the above black toner B1, and otherwise the same as in the case of the black toner B1 Thus, a black toner B3 was obtained.

(Black Toner B4) In producing the black toner B4, toner particles using the polyester resin D were obtained in the same manner as in the case of the black toner B1, and then externally added to the toner particles. As an agent, hydrophobic silica (HD130: H1303) was added in an amount of 0.4.
% By weight, and the above-mentioned hydrophobic titania B was added at a ratio of 0.6% by weight, and these were mixed by a Henschel mixer and subjected to an addition treatment to obtain a black toner B4.

(Black Toner B5) In producing the black toner B5, toner particles using the polyester resin A were obtained in the same manner as in the case of the black toner B3, and then externally added to the toner particles. As an agent, hydrophobic silica (HD130: H1303) was added in an amount of 0.4.
% By weight and the above-mentioned hydrophobic titania B were added at a ratio of 0.6% by weight, and these were mixed by a Henschel mixer and subjected to an addition treatment to obtain a black toner B5.

Next, the above-mentioned cyan toners C1 to C4,
Magenta toners M1 to M4 and yellow toners Y1 to Y
4 and black toners B1 to B5, as shown in Table 2 below, a cyan toner, a magenta toner, a yellow toner, and a black toner were selected, and full-color developments of Examples 1 to 4 and Comparative Examples 1 to 3 were performed. Toner was obtained.

[0077]

[Table 2]

Next, the above Examples 1 to 4 and Comparative Examples 1 to
Difference ΔT of 3 cyan used in the full-color toner for developing magenta, and flow starting temperature Ti ₁ of the binder resin in the yellow color toner, the softening point Tm _1, the flow starting temperature Ti ₁ and its softening point Tm _{1 1,} the outflow start temperature Ti ₂ of the binder resin in the used black toner, the softening point Tm ₂ , and the softening point Tm ₂
ΔT ₂ between the color toner and the outflow start temperature Ti ₂ , and the difference (ΔT ₁ −ΔT ₂ ) between ΔT ₁ in the used color toner and ΔT ₂ in the black toner are shown in Table 3 below.

[0079]

[Table 3]

Next, the above Examples 1-4 and Comparative Examples 1-3
An image was formed using each of the full-color developing toners described above, and the gloss balance of the full-color image, the durability of the color toner, and the durability of the black toner were examined.

Then, in Examples 1 to 3 and Comparative Examples 1 and 2,
In forming an image using each full-color developing toner of No. 2, the developing units 31C and 31 of the full-color developing device 30 in the full-color printer shown in FIG.
M, 31Y, and 31Bk are supplied with respective toners to form an image.

Here, in the full-color printer shown in FIG. 1, a charging brush 11 for uniformly charging the surface of the photosensitive drum 10 to a predetermined potential is provided around the photosensitive drum 10 which is driven to rotate. A cleaner 12 for scraping off toner remaining on the body drum 10 is provided.

A laser scanning optical system 20 for scanning and exposing the photosensitive drum 10 charged by the charging brush 11 with a laser beam is provided. The laser scanning optical system 20 includes a laser diode, a polygon mirror, f
It is a well-known type having a built-in θ optical element, and print data for each of cyan, magenta, yellow, and black is transferred from a host computer to its control unit. The laser scanning optical system 20 sequentially outputs a laser beam based on the above-described print data for each color, scans and exposes the photosensitive drum 10, and thereby places a static image for each color on the photosensitive drum 10. Electrostatic latent images are sequentially formed.

The full-color developing device 30 that supplies toner of each color to the photosensitive drum 10 on which the electrostatic latent image is formed to perform full-color development is provided around the support shaft 33 around cyan, magenta, and cyan. Four color developing units 31 containing non-magnetic one-component toners of yellow and black, respectively.
C, 31M, 31Y, and 31Bk are provided, rotate around the support shaft 33, and each of the developing devices 31C, 31M, and 3B.
1Y and 31Bk are guided to a position facing the photosensitive drum 10. Further, each developing device 31C, 31M, 31Y, 31 in the full-color developing device 30 is used.
In Bk, toner regulating members 34a and 34b are pressed against the outer peripheral surface of the developing sleeve 32 that rotates and transports the toner, and regulates the amount of toner transported by the developing sleeve 32 by the toner regulating members 34a and 34b. At the same time, the conveyed toner is charged.

Then, as described above, the laser scanning optical system 2
Each time an electrostatic latent image of each color is formed on the photosensitive drum 10 by 0, the full-color developing device 30 is rotated about the support shaft 33 as described above, and the toner of the corresponding color is stored. Developing units 31C, 31M, 31Y, 31
Bk is sequentially guided to a position facing the photosensitive drum 10,
The developing sleeve 32 in each of the developing devices 31C, 31M, 31Y, and 31Bk is brought into contact with the photosensitive drum 10 to charge the photosensitive drum 10 on which the electrostatic latent images of the respective colors are sequentially formed as described above. The development is performed by sequentially supplying the toners of the respective colors.

An endless intermediate transfer belt 40 that is driven to rotate is provided as an intermediate transfer member 40 at a position downstream of the full-color developing device 30 in the rotation direction of the photosensitive drum 10. The transfer belt 40 is driven to rotate in synchronization with the photosensitive drum 10. The intermediate transfer belt 40 is pressed by a rotatable primary transfer roller 41 and comes into contact with the photosensitive drum 10.
A secondary transfer roller 43 is rotatably provided at a portion of the support roller 42 that supports the recording medium S. The recording member S such as a recording sheet is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. I have.

Further, in a space between the full-color developing device 30 and the intermediate transfer belt 40, a cleaner 50 for scraping toner remaining on the intermediate transfer belt 40 is provided.
Are provided so as to be able to contact and separate from the intermediate transfer belt 40.

A paper feeding means 60 for guiding a recording material S such as recording paper to the intermediate transfer belt 40 includes a paper feeding tray 61 for accommodating the recording material S and a recording material S accommodated in the paper feeding tray 61. A sheet feed roller 62 for feeding one sheet at a time, and a recording member S fed in synchronization with an image formed on the intermediate transfer belt 40 are transferred between the intermediate transfer belt 40 and the secondary transfer roller 43. The recording member S sent between the intermediate transfer belt 40 and the secondary transfer roller 43 in this manner is pressed against the intermediate transfer belt 40 by the secondary transfer roller 43. Then, the recording member S presses and transfers the toner image from the intermediate transfer belt 40.

On the other hand, the recording member S onto which the toner image has been pressed and transferred as described above is guided to the fixing device 70 by the conveying means 66 constituted by an air suction belt or the like. The transferred toner image is fixed on the recording member S, and thereafter, the recording member S is discharged to the upper surface of the apparatus main body 1 through the vertical conveyance path 80.

When forming a full-color image using this full-color printer, first,
The photosensitive drum 10 and the intermediate transfer belt 40 were driven to rotate in the respective directions at the same peripheral speed, and the photosensitive drum 10 was charged to a predetermined potential by the charging brush 11.

The photosensitive drum 10 thus charged was exposed to a cyan image by the laser scanning optical system 20 to form an electrostatic latent image of the cyan image on the photosensitive drum 10. Thereafter, a cyan toner is supplied from a developing device 31C in which the photosensitive drum 10 contains the cyan toner to develop a cyan image, and an intermediate transfer is performed on the photosensitive drum 10 on which the cyan toner image is formed. The belt 40 is pressed by the primary transfer roller 41,
The cyan toner image formed on the photosensitive drum 10 was primarily transferred onto the intermediate transfer belt 40.

After the cyan toner image is transferred to the intermediate transfer belt 40 in this manner, the full-color developing device 30 is rotated about the support shaft 33 as described above, and the developing device containing the magenta toner is rotated. 30M photoconductor drum
The photosensitive drum 10 charged by the laser scanning optical system 20 is exposed to a magenta image to form an electrostatic latent image in the same manner as in the case of the cyan image described above. The electrostatic latent image is developed by a developing device 30M containing magenta toner, and the developed magenta toner image is primarily transferred from the photosensitive drum 10 to the intermediate transfer belt 40. Similarly, the yellow image and the black image Exposure, development, and primary transfer were sequentially performed to form a full-color toner image on the intermediate transfer belt 40 by sequentially superimposing cyan, magenta, yellow, and black toner images.

When the final black toner image is primary-transferred onto the intermediate transfer belt 40, the recording member S is sent by the timing roller 63 between the secondary transfer roller 43 and the intermediate transfer belt 40. The recording member S was pressed against the intermediate transfer belt 40 by the next transfer roller 43, and the full-color toner image formed on the intermediate transfer belt 40 was secondarily transferred onto the recording member S.

When the full-color toner image is secondarily transferred onto the recording member S, the recording member S is guided to the fixing device 70 by the above-described conveying means 66, and is transferred by the fixing device 70. The full-color toner image is fixed on the recording member S, and then the recording member S is discharged onto the upper surface of the apparatus main body 1 through the vertical conveyance path 80.

On the other hand, when an image was formed using the full-color developing toners of Example 4 and Comparative Example 3, each of the toners was mixed with a carrier manufactured as described below. The ratio was adjusted to 6% by weight, and each developer mixed with the carrier was mixed with a commercially available full-color copying machine (CF7, manufactured by Minolta Co., Ltd.).
0) to perform image formation.

(Manufacture of Carrier) First, 10 parts of methyl ethyl ketone were placed in a 500-ml volumetric flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube, and a dropping device.
0 parts by weight were added. On the other hand, separately in a nitrogen atmosphere
At 0 ° C, 36.7 parts by weight of methyl methacrylate, 5.1 parts by weight of 2-hydroxyethyl methacrylate, and 5 parts by weight of 3-methacryloxypropyltris (trimethylsiloxy) silane are added to 100 parts by weight of methyl ethyl ketone.
A solution prepared by dissolving 8.2 parts by weight and 1 part by weight of 1,1′-azobis (cyclohexane-1-carbonitrile) was prepared, and the solution was dropped into the flask over 2 hours and aged for 5 hours. To obtain a resin.

Next, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1%) was used as a crosslinking agent so that the OH / NCO molar ratio became 1/1. After adding
It was diluted with methyl ethyl ketone to prepare a coating resin solution having a solid ratio of 3% by weight.

[0098] The coating resin solution was applied to a core material composed of calcined ferrite powder (F-300, manufactured by Powdertech Co.) having an average particle size of 50 µm so that the coating resin amount was 1.
After coating with a spira coater (manufactured by Okada Seiko Co., Ltd.) and drying the carrier, the carrier was allowed to stand in a hot air circulating oven at 160 ° C. for 1 hour and fired. After the product is cooled, the ferrite powder bulk is crushed by a sieve shaker equipped with a 106 μm and 75 μm screen mesh, and mixed with each full-color developing toner of Example 4 and Comparative Example 3. I got

Then, an image was formed using the full-color developing toners of Examples 1 to 4 and Comparative Examples 1 to 3 as described above, and the gloss balance of the full-color image, the durability of the color toner, and the durability of the black toner The properties were examined and the results are shown in Table 4 below.

Here, the gloss balance of the full-color image is determined by forming a full-color image using a copier test pattern AR-5 (manufactured by DataQuest) and visually checking the gloss between the black image portion and the color image portion in the full-color image. The balance was evaluated. When the gloss between the black image portion and the color image portion was not uncomfortable, the result was O. When the gloss between the black image portion and the color image portion was slightly different and there was no problem in practice, If the difference in gloss is remarkable (for example, if the black image part has a matte tone with respect to the gloss of the color image part or the gloss of the black image part is too emphasized with respect to the gloss of the color image part) Is indicated by x.

Regarding the durability of the color toner, in each of the above-described Examples 1 to 3 and Comparative Examples 1 and 2, the toner regulating member was used at the time when 3000 images were formed using the cyan toner. Check if toner is agglomerated and fixed on the developing sleeve or not. ○: No agglutination or sticking occurs, △: Slight occurrence but no practical problem When there is the above problem, it is indicated by x, and in the case of Example 4 and Comparative Example 3, fog was found on the image by visual evaluation at the time when 10,000 images were output using cyan toner. The case where there was almost no occurrence was indicated by 、, the case where some fog occurred but there was no practical problem, and the case where there was much fog and there was a practical problem was indicated by x.

Further, regarding the durability of the black toner,
In each of Examples 1 to 3 and Comparative Examples 1 and 2, at the time when 5,000 images were printed using the black toner, whether the toner was aggregated and fixed to the toner regulating member or the developing sleeve. The results are shown in the table below: ○: No aggregation or sticking occurred; Δ: Slightly occurring but no practical problem; X: toner sticking and a practical problem indicated; 4 and Comparative Example 3 were evaluated by visual evaluation at the time when 20,000 sheets of image were formed using the black toner.い る indicates that there is no practical problem, and X indicates that there is a lot of fog and there is a practical problem.

[0103]

[Table 4]

Here, the gloss balance of the full-color developing toner of Example 3 had no problem in practical use. However, there was a slight difference in gloss between the full-color image portion and the black image portion. Although the gloss balance of the developing toner had no practical problem, the gloss of the black image portion was too emphasized. On the other hand, the full-color developing toner of Comparative Example 2 had a problem that the gloss difference between the full-color image portion and the black image portion was very large.

As is clear from the results, Examples 1 to
In each full-color developing toner of No. 4, a good full-color image having a small difference in gloss between the color image portion and the black image portion can be obtained, and the durability of the color toner and the black toner is good. This has enabled stable image formation.
On the other hand, in each of the full-color developing toners of Comparative Examples 1 to 3, the difference in gloss between the full-color image portion and the black image portion becomes remarkable, and a good full-color image cannot be obtained. There is a problem that the durability of the black toner is poor, and it is impossible to stably form a full-color image or a monochrome image.

[0106]

As described in detail above, in the full-color developed toner according to the present invention, in addition to full-color image formation, even when a normal monochrome image using only black toner is frequently formed, Only the black toner does not deteriorate faster than other color toners such as the cyan toner, and when a full-color image is formed, the black image portion formed by the black toner and the color formed by the color toner Differences in gloss and the like from the image portion are less likely to occur.

As a result, when an image is formed by using the full-color developing toner according to the present invention in a full-color image forming apparatus, the portion of the black image formed by the black toner and the color image formed by the color toner are formed. It is possible to obtain a good full-color image and a stable formation of a monochrome image, without causing a sense of discomfort between the portions.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing an example of a full-color image forming apparatus for forming a full-color image.

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junichi Tamaki 2-3-1-13 Azuchicho, Chuo-ku, Osaka-shi Osaka International Building Minolta Co., Ltd. (72) Inventor Ichiro Izumi 2-chome Azuchicho, Chuo-ku, Osaka-shi No. 13 Osaka International Building Minolta Co., Ltd. (72) Inventor Hiroyuki Fukuda 2-3-13 Azuchicho, Chuo-ku, Osaka City Osaka International Building Minolta Co., Ltd. (56) References JP-A-6-19197 ( JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 9/09

Claims (1)

(57) [Claims] 1. A full-color developing toner used in a full-color image forming apparatus that forms a full-color image by developing a predetermined color using a cyan toner, a magenta toner, a yellow toner, and a black toner.
The cyan toner, the flow starting temperature Ti ₁ is 80 to 100 ° C. of the binder resin in the color toner of magenta toner and yellow toner, the softening point Tm ₁ is 90 to 12
0 ° C., the difference Δ between the softening point Tm ₁ and the outflow starting temperature Ti ₁
T ₁ (= Tm ₁ −Ti ₁ ) is 10 to 20 ° C., and the outflow start temperature Ti ₂ of the binder resin of the black toner is
Is 90 to 110 ° C., the softening point Tm ₂ is 110 to 130 ° C.,
The difference between the flow starting temperature Ti ₂ and the softening point Tm ₂ [Delta] T ₂
(= Tm ₂ −Ti ₂ ) is 15 to 30 ° C., and the difference (ΔT ₂ −ΔT ₁ ) between ΔT ₂ in the black toner and ΔT ₁ in each color toner is 3 to 13 ° C.
A toner for full-color development, characterized in that: